Liquid crystals with a large negative dielectricanisotropy are difficult to align vertically on silicon oxide surfaces and sometimes even on polyimides. An interesting method has been found to generate high quality vertical alignment by doping the host liquid crystal with materials that have a cyanogroup along their long molecular axis. The effect is explained by considering both long range and short range interactions between liquid crystal and the alignment layer. Using this method we propose a way to design new liquid crystal mixtures with large negative dielectricanisotropy that have improved aligning ability for applications requiring vertical alignment. The method also allows for increased birefringence.

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Copyright 2006 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in J. Appl. Phys. 99, 123523 (2006) and may be found at http://dx.doi.org/10.1063/1.2209189.